S-91327A303 3/8"-16 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Secure vibration resistance with integrated nylon patch thread locker that maintains locking performance from -50° to 250°F, preventing loosening in dynamic applications.
• Enhanced durability and corrosion resistance thanks to 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments.
• Precise alignment and smooth rotation with a standard shoulder fit and controlled diameter tolerance, reducing wear on mating components.
• High strength and reliability offering 70,000 psi tensile strength and Rockwell B55 hardness for demanding mechanical assemblies.
• Easy installation and removal with a knurled socket head and 1/4" hex drive, providing superior grip and torque application.
• Accurate thread engagement with Class 3A thread fit and UNC coarse threads, ensuring consistent fastening in high-vibration settings.
• Broad compatibility and compliance meeting ASME B18.3 standards, RoHS 3, and REACH regulations for global industrial use.

Professional Applications & Engineering Value

This 3/8"-16 UNC shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and heavy-duty equipment. The 18-8 stainless steel material and passivated finish provide exceptional resistance to corrosion and wear, extending service life in moist or chemically aggressive environments. Its integrated nylon patch thread locker secures fasteners against vibration-induced loosening, a common failure point in motors, conveyors, and rotating assemblies. The knurled socket head with hex drive allows for efficient installation in confined spaces, while the precise shoulder diameter and length tolerances ensure accurate component positioning, reducing misalignment and improving overall system reliability. Ideal for use in industrial shoulder screw applications such as pivots, shafts, and guides, this screw delivers consistent performance where dimensional stability and locking security are paramount.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit with UNC coarse threads for reliable engagement, and adheres to ASME B18.3 manufacturing specifications for dimensional accuracy. It is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and suitability for various industrial sectors. The shoulder diameter tolerance is -0.004" to -0.002", and shoulder length tolerance is -0.005" to 0.005", supporting precise assembly requirements.